Fix #7831

Original patch by @j-a4

The goal here isn't to prevent these hashtags from existing, but just to strongly curtail their usage; The hashtags may still exist in the database via federated status, or from being created prior to this feature.

Sidekiq sometimes throws errors for users that have more pinned items
than the allowed by the local instance. It should only validate the
number of pins for local accounts.

Comparison was downcasing only one side, therefore if previously
existing account had a non-lowercase spelling, it would be ignored
when checking for duplicates.

New rake task `mastodon:maintenance:find_duplicate_usernames` will
help find constraint violations that might have occured from the
presence of this bug.

Bump version to 2.3.3

* Permit dots in usernames with conditions

- Dot cannot be the start or end of username
- a.lice and al.ice are considered the same during sign-up

* Fix regex mixin flags

* add pam support, without extra column

* bugfixes for pam login

* document options

* fix code style

* fix codestyle

* fix tests

* don't call remember_me without password

* fix codestyle

* improve checks for pam usage (should fix tests)

* fix remember_me part 1

* add remember_token column because :rememberable requires either a password or this column.

* migrate db for remember_token

* move pam_authentication to the right place, fix logic bug in edit.html.haml

* fix tests

* fix pam authentication, improve username lookup, add comment

* valid? is sometimes not honored, return nil instead trying to authenticate with pam

* update devise_pam_authenticatable2 and adjust code. Fixes sideeffects observed in tests

* update devise_pam_authenticatable gem, fixes for codeconventions, fix finding user

* codeconvention fixes

* code convention fixes

* fix idention

* update dependency, explicit conflict check

* fix disabled password updates if in pam mode

* fix check password if password is present, fix templates

* block registration if account is maintained by pam

* Revert "block registration if account is maintained by pam"

This reverts commit 8e7a083d65.

* fix identation error introduced by rebase

* block usernames maintained by pam

* document pam settings better

* fix code style

* Implement BlacklistedEmailDomain

* Use Faker::Internet.domain_name

* Remove note column

* Add frozen_string_literal comment

* Delete unnecessary codes

* Sort alphabetically

* Change of wording

* Rename BlacklistedEmailDomain to EmailDomainBlock

* Pinned statuses

* yarn manage:translations

URI.extract is too strong, not limited to URLs, matched real text.
Same issue was present in language detector.

* Count all URLs in text as 23 characters flat, do not count domain part of usernames

* Add new status text counting logic to web UI

* Bring Toot button in line with counter

Both should use stringz I guess

* Use grapheme_length for character count

* Added support for configurable reserved usernames

* Added reserved usernames from mastodon issue 1355

* Fix reserved usernames

* Stricter whitelist rules

* Linting

* Added spec for blacklisting

* Test subdomain blacklist on domain whitelist

* No need to split

* Change spec name

* Fix #2119 - Whenever about to send a HTTP request, normalize the URI

* Add test for IDN request in FetchLinkCardService

* Perform IDN normalization on domains before they are stored in the DB

* Add `Presenters` group to SimpleCov configuration

* Move validators to app/validators, add to simplecov config

Federate spoiler_text using warning attribute on <content /> instead of a <category term="spoiler" />
Clean up schema file from accidental development migrations